Electrical switch-board for metallic circuits



(No Model.)

- -T. N.VAIL. ELEGTRiGAL SWITCH BOARD FOR METALLIC CIRCUITS. No. 261,187. v Patented July 18,'188'2..

m1. 720.2. V Z 3%; 2. i.

a y :e b Z2 1; 2': a f: 22 Z P F qdescribed satisfactorily and with celerity in ton,in the county of Suffolk and State of Mas.

. rnnononn uvAIn, or BOSTON, iiAssAcuU-su'rrs ELECTRICAL SWITCH-BOARD FOR METALLiO-CtRCUiTS.

SPECIFICATION forming partof- Letters Batent no. 261,137, dated July 18, 1882.

Application filed Apnl28,1882. (we model.)

To all whom it may concern:

Be it known that 1, Tune. N.VA1L, ot'Bo'ssachusetts, have invente'dfcertaiu Iinprovements in Electrical Switch-Boards for Metallic Circuits, of which the following is a specification. v 4

My invention relates toimprovements in electric switch-boards, whereby special arrangements of circuits may be made and operated,

and the connection, disconnection, and interchanging of metallic circuits and loops con- I veniently and quickly efl'ected.

It has been known from the earliest introduction of the speaking-telephone that when eachcircuit is composed of butonewire connecting any two points it is often strongly influenced by electrical vibrations a-nddisturbances received by electrical induction from other and parallel conducting wires conveying telegraphic or other strong electrical currents, and sometimes, if the wires are" of considerable length, the telephonic messages traversing one wire arc-from the same cause repeated on ad- 2 jacent wires. It is often found that these distnrbing inducti\-'einiluences cause such acoufusion of sounds that the telephonic articulaions cannot be understood; and in the latter case, in which the telephonic currents are induced from one wire to another, it is obvious that all privacy of communication is destroyed.

As a remedy for this objectionable feature inieiephonic intercommunication, it has been proposed to employ a metallic return-circuit for each conducting-wire, instead of using a single wire terminating at the earth at each of the two distant points connected by theline. Such an arrangement is described and shown in the English patent of L. D. B. Gordon, No. 2,089, ofthedate September 15,1855, in which the return-circuit runs parallel with but is insulated from the outgoing wire, and the pron-- imity of the two wires toone another and with reference to neighboring wires issnch that disturbing effects in one of the wires will be neutralized and counteracted by the-disturbing" efi'ects simultaneously-produeeclin the other and complementaryreturn-circuit but it has been found very difficult in practice to operate metallic or looped circuits arranged as central-office or telephone-exchange systems,

vide for the cross-connection oftwo centralofiice terminals, we have to provide for the multaneousinterconnection or disposition of four line terminals; and to accomplish this in a convenient and expeditious manner is the object of my invention, which consists in the combination of a series of metallic circuits or loops with a switch-board adapted for the rapid and simple interchanging of such cirterconnection' of metallic circuit-lines, and in the combinatiou,with a switch-board arranged for thereception of metallic circuit-lines, of a connecting-plug which is fitted with two sepathereby at each insertion to make contact with and betweenfourconnectingswitch-board conducting bars, plates, or strips.

transverse conducting-strips are represented by bars, and shows two metallic circuit-lines are sections showing arrangement of crossrods. Fig. 4 represents a board embodying two series of wires stretched tightlyat right tion of the said wire board on lineirw. Fig.

adapted for use in the switch-board shown in Fig. 1,. Figs. 7, and 8, and 9, and 10 are respectively elevation andcross-sectiou views of other varieties of plugfor'the same board. Figs. 11, 12, 13, and 14 are similar views of plugs adapted for use with the wire switch-board shown in Figs. 4 and 5.

A in either board is a base board or frame and b, which can conveniently be made of brass or any similar metal or alloy. Theyare usuallygialthough not necessarily, arranged at right angles tdoneanother, and each bar of theseriesb is so fixed in the base-board, as shown in Figs. 2 and 3, as to cross over the any of them.- preferably those shown as vertical, b, to the inasmuch as, instead of merely having to prorate conduct-in g surfaces or plates, and ad a pted connecting with sub-stations. Figs. 2 and 3- the same principle, but constructed simply of 6 is. a perspective view or" a connecting-plug bars of the other series, c,without touching I connect the bars of oneseries,

cuits, in a-switch-board providing for such in- In the accompanying drawings, which illustrate my invention, Figure 1 is a diagrammatic view of a switch-board in whichthe angles to one another. Fig. 5 isa cross-secof wood, upon which,in Fig. 1, are ranged two series of conducting bars, strips, or plates, a

wires entering from the line-wires, and Ileave a similar manner, and in eachicase it warmers:-

with the upright bars of the switch-board thethose crossing transversely normally insulated from any other conducting-body whatsoever. At the point q of each upright metallic bar '11,! connect the respective line-wires 1, 2, 3,

and 4 of the circuitsNo. 1 and No. 2, and my circuits and apparatus are so constructed and arranged that the same'circuit, No. 1, leading out by wire 1 from'switch-bar b to the distant sub-station S, insteadof being there terminated at an earth-plate", is, after passing through the sub-station apparatus, returned to the centralstation switch-board A, by a second or return wire, 2, which is connected, as shown, to the second upright strip, 1), at the point q, thus forming in each circuit so constructed anabsolute metallic circuit or loop fromthe central station to the sub-station andre'tiir'ri. ..-Each circuit is connected with theswitchiboard in fore be seen that after thelines are connected lower extremity, p, of each bar forms thevirtnal terminal of its respective circuit wire." T

In practice the pairof terminals p'pertaining to each line will be connected with an in-. dicating device-such as an annunciator- -the wire 1 thus being connected with one wire of the annunciator helix and the wire2 with the other. As, however,'this forms no part of my inventiomit is hotshown in the drawings.

For the convenien'toperationof circuits constructed as hereinheforedescribed, the conducting-bars, both vertical and horizontal, are arranged in pairs, b b, a a, andthus at theintersecting pointof the two series a species of plug-socket is formed, having four separate metallic sides as its linear boundaries, two of which, I) and b, are connected with the two ends of the line-circuit, and the other two, a and a, are'insulated from any other conductor,

and thus are enabled to serve as connectinglinks when aQplug specially conformed, as hereinafter,described, is inserted within the plug-socket formed by the intersection of'the vertical and horizontal bars.

' Fig.4 is a board constructed upon the same general principle of metallic circuits, and shows four pairs of vertical metallic conductors I) Z which in thisfease are wires tightly drawn over the su'rfaceof the board, as shown in Fig. 5. Four pairs of horizontal conducting-wires a. u are also shown, which'liliewiseare tightly stretched under the vertical series. The line- I wires are connected in a precisely similar manner ito those of'Fig. l, and, as in Fig. 1, the connecting piug socket is formed by the'inter section of one pair of the vertical conductors wit-hfone pair of the horizontal conductors. A plug of spec al character is obviously requisiteiuconnection with this" board, and it is, aiso obvious thatin a board such as that shown I in 'Fi g. 1, fitted 'with com parativel y-ri gid conducting-bars, the 'conducting-suriaces of the 'connecting-plug-mu'st possess a certain degree of. elasticity or resiliency in order to adapt itself to a perfect'fit 'in the plng -socket. If, on

the contrary, a heard of similar characteristics The pin 6 is also tiixed to this conducting material. Curved plates of metal,

(I d,'are placed on two of the opposite sides of the nucleus 0, and fastened on with small screws. -El -his,plug is to be inserted in its socket diagonally, and is then held firmly, as only; whenso placed is there suflicient space 'for its insertion, and when once inserted it cannot turd-round, the plates 01 being wider than anyone side ot' the plug-socket.

g ,,,The plug'showf in Figs. 7 and 8 also has a handle, P, and non-conducting nucleus 0, and for its conducting-surfaces is provided with metallic angle-plates d, which are attached byone side only to the nucleus, so as to impart suflicient resiliency to them to produce a firm contact upon the sides of the plug-socket. This variety is shown as inserted in tbe'socket formed by the intersection of the horizontal bars a a and the vertical bars I) h of the wires- 1 and 2 in' Fig. 1 and on alarge scale in Fig. 8, where the switch-bars are represented by dotted lines. Asquare pin, e,"is shown as ex tending from the-inner end ot'fthe "non-cow ducting portion of the plug. 'This, whenthe plug is inserted, fits in a square hole, a, in the base-board A,and serves as a guide for the' V proper insertion of the plug, in order that one of its angle-platesd may alwaysbe'brought into contact with onevertic'al and one horiother angle-plate, into contact with the other vertical and horizontal bars'of the pair.

'zontal conducting bar of each'pair and the iio ' Figs. 9 and 10 show still another variety of v connecting-plug, the conducting-plates d of clearly shown in the sectional viewin Fig. 10. us and adapted for insertion in the hole 0.

The plugs shown in Figs. 11 and 13 and in cross-section in Figs. 12 and 14 are madeespecially adaptedfor use with the board shown in Figs. 4 and 5. Fig. 13, besides being fitted with angle-plates for .co'nducting-surtaces, is provided with grooves f, which, when the lug is inserted in any ofthe squaresformed by the intersection of a vertical and horizontal pair, clasp the wires which in this board represent the conducting-bars, and thus make-a good electrical contact. Figs. ii. and 12 simply show two angle-plates d, rigidly'fi'xed upon the non-conducting portion oi theiplng.

I In all the figures it will be seen that the plugs are squared and are adapted to fit square sockets, and that the contact-plates are so arranged as to be out y one of" the diagonals which have their corners rounded, asinore of the square socket when inserted. They will thus connect the strips adjacent to their respective ends of the said diagonal. The arrangement may for convenience be termed the diagonal arrangement of the contactplates.

b to line 3 of No. 2 circuit to sub-station S,

returning via line 4 to upright strip upper conducting-plate of plug P, cross-strip a,

circuit, thus circuit.

upper plate of plug P, and to upright strip 6, back'to the starting-point g on line 1 of No. 1 completing a continuous metallic 1t hasprior to my invention been customary to use for the cross connection of two loops, as described, four plugs, one'for the crossing- I point of each upright strip with itscorrespond .ing horizontal strip. For example, strip 1) ot No, 1 would be fixed by a single connecting:

. plug ,to the horizontal bar av and'strip b'i ot" .circ'uit No; l to' horizontal bar a','No. 2 being readily pushed slightlytoeither side upon th' similarly connected. It is clear, therefore, that both time andapparat-us are advanta geously minimized by the use of my invention,

inasmuch as two plugs are in each interconnection dispensed with,and the-time which.

would be lost by the act of inserting themis saved. f'

.When the boardshowh in Fig. .4 iseniployedx :the wires which form the conductingstrips d ucing a good electrical contact.

r. *to switch-boards of any specialmethod ot con ,being tightly stretched overthe board, will be insertion of the p 'ug,.and when the said put is fully inserted will close tightly uponit, .pro

Ldo not in this specification confine struction, as the essence of my. invention lies in the arrangement of certain well-known instrumentalities' in such a manner that the insertion of two plugs shallinterconnect the two wire-terminals of one metallic circuit or loop with the two terminals of any other similar 100?, so as toproduce a continuous circuitcomposed of the said two loops, wherebya sub-station locatedat any part of oneof the said loops is placed indirect electrical connec tion with a sub-station at any part of the other loop through the cen trail-station switch-board. It is evident, therefore, that any switch-board in which the intersecting conducting-strips or their equivalents are arranged in pairs can be .used to carry out my invention.

I claim-'- 1. The combination, in atelephone-exchange system", with a series of metallic circuits or loopdmes, of a switch-hoard havingstrips,

bars, or plates arranged in pairs, and plugs or connectors for establishing the connection of the loop-lines with each other through said strips, bars, or plates, 'the latter extending across the switch-board, and being for their continuity i'ndepemlentot' the plugs or con-' nectors, substantially its-described. V 2. In a switchboard, the two setsor series of intersecting insulated strips arranged 1n pairs, in combination with plugs or connectors for connecting the strips of any pair with the strips of an intersecting pair, the said strips being electrically continuous independent of the plugs or connectors, substantially as described.

3. In an electrical switch-board or cou1niu-' .tator, the conducting strips or bars, arranged in pairs, each pair permanently connected with the two, ends of a metallic or loop circuit, and the connecting bars or strips, also arrangedin pairs, and disposed transversely with reference to the line-strips, in combination with the plugconnector provided with separate contactplates, each adapted to make contact simultaneously with one linestripand one connecting-strip, the connecting strips or bars of a pair having normally no electrical connection with each other, for the purposes set forth. 7

--I 41 A switch-board consisting of a series of conducting};line-'stripsor their equivalents,

arranged in pairs for the reception of both ends of' a 'line-circnit, a transverse series of connecting-strips, or equivalents therefor, also arranged inpai'rs,each paircrossing each pair :li'x ie-strips'in suchga manner as to form by ach'-.in.ter tion ahole or plug-socket having .-for'itsllinear'lboundary a portion'of eachof the :fourintersectingstrips, "and a plug or circuit eonn'ectofrl furnished with two contact-plates iuctingfportiontof the plug, and placed-oppositely to .QHB' -3DOI11B I, whereby when the said plug is insertedjeach one 'of the pair of line'- stri'psjis respeotirelyi connected with one of. the pairof connecting or cross strips, substantially as and for the purposedescribcd.

, i 5, c'llhecombination, in atelephone-exchange system, of acompound signalingcireuit composed' of, two metallic circuits or loops, each p lbs insulated fronif one'1another 'by the non coua normally forming a main line, two pairsoi switch-board conducting bars, plates, or strips, each pair permanently connected-with the two terminals of its own line, a 'pair of switchboard connecting bars or strips crossing trans- ,versely both pairs-of line-str'ips,but normally insulated therefrom and without electrical connection with each other, and a plug-connector constructed, substantially as described, with two separate conducting-surfaces thereon, and adapted for insertionin the plug-sockets prod need by the intersection of the transverse pair of strips with the two pair of line-strips, as and for the purpose specified.

6. In an electrical switch-board, plug-sockets formed by the intersection of continuous.

line strips, bars, plate s er wires, arran ged in pairs, with continuous transverse connectingeonductors oflike character, likewise arranged in pairs, as and for the piirpose specified.

7. In a switeh boalzd, strips, bars, or plates arranged toleave one-or more square sockets between them, in eoiilbination with plugs adapted to fitsaid sockets, and having contact-pieces arranged as indicated, so that when inserted they connect adjacent strips, bars, or

IO plates, substantially as described.

8. A switch-plug adapted forinsertion in asquare socket, and having contact-plates (i agonally arranged so as to connect; the con duetors or adjacent sides of the square sockcts, substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 25th day of April, 1882.

' THEO. N. VAIL.

Witnesses: A

FRED BARTLEET, Geo. WILLIs PIERGE. 

